Combining his skill as a master goldsmith and his love for drawing, artist John Schipp has made a creative set of coins under the title Grandma Schipp's Family Album. They're an ongoing collection of fictional characters all created on actual coins.
The Hobo Nickel is a sculptural art form involving the creative modification of small-denomination coins. The nickel was a favored coin for this purpose because of its size, thickness and relative softness. However, the term “hobo nickel” is generic, as carvings have been made from many different denominations. Due to its low cost and portability, this medium was particularly popular among hobos, hence the name.
If you're curious about how Schipp created these Hobo Nickels, you can read all about it here. (He uses a laser welder, a black Sharpie, and a square graver among other tools.)